1. Field of the Invention
The invention relates generally to the field of thermoplastic materials, particularly articles of manufacture formed thereof and methods for making such thermoplastic articles.
2. Description of the Prior Art
Linear polyethylene has long been known to exist in high density and low density forms, each form having properties suited to certain uses. Mixtures of high density and low density polyethylene powder have previously been used as a surfacing for ferrous metal surfaces, the two materials being mixed and applied such as by spraying to a heated metal surface. U.S. Pat. No. 4,007,298 discloses such a coating formed of high density and low density polyethylene in a volumetric ratio of from 1:1 to 1:3. High and low density polyethylene have also previously been extruded in sheet form for varying purposes, sheets of high density polyethylene having a high tensile strength but a relatively low impact strength. In effect, high density polyethylene forms a stiff sheet-like article, such an article tending to crack and retain a crease when folded or bent in normal use. Further, sheet material formed of high density polyethylene is difficult to die cut and print with uniform pressure due to the fact that such sheet material has a natural "curl" which prevents ready maintenance of the sheet material in a flat conformation. Sheet material formed of low density polyethylene has a low tensile strength and is too flexible for applications which subject the material to heavy use. The present invention provides a sheet-like article of manufacture and a method for making such an article, the article comprising a mixture of high density and low density polyethylene which can be extruded in sheet form to provide a material having a desired flexibility and tear strength and which can be printed or written upon with ease compared to prior art polyethylene sheet materials.